# High flux polarized gamma rays production: first measurements with a four-mirror cavity at the ATF

1 ThomX
LAL - Laboratoire de l'Accélérateur Linéaire
Abstract : The next generation of e+/e- colliders will require a very intense flux of gamma rays to allow high current polarized positrons to be produced. This can be achieved by converting polarized high energy photons in polarized pairs into a target. In that context, an optical system consisting of a laser and a four-mirror passive Fabry-Perot cavity has recently been installed at the Accelerator Test Facility (ATF) at KEK to produce a high flux of polarized gamma rays by inverse Compton scattering. In this contribution, we describe the experimental system and present preliminary results. An ultra-stable four-mirror non planar geometry has been implemented to ensure the polarization of the gamma rays produced. A fiber amplifier is used to inject about 10W in the high finesse cavity with a gain of 1000. A digital feedback system is used to keep the cavity at the length required for the optimal power enhancement. Preliminary measurements show that a flux of about $4\times10^6 \gamma$/s with an average energy of about 24 MeV was generated. Several upgrades currently in progress are also described.
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Conference papers
2nd International Particle Accelerator Conference (IPAC'11), Sep 2011, San Sebastian, Spain. Joint Accelerator Conferences Website, TUPO002, pp.1446-1448, 2011

http://hal.in2p3.fr/in2p3-00635065
Contributor : Sabine Starita <>
Submitted on : Friday, July 27, 2012 - 3:12:54 PM
Last modification on : Wednesday, July 20, 2016 - 9:44:52 AM

### Identifiers

• HAL Id : in2p3-00635065, version 1
• ARXIV : 1110.3243

### Citation

N. Delerue, J. Bonis, I. Chaikovska, R. Chiche, R. Cizeron, et al.. High flux polarized gamma rays production: first measurements with a four-mirror cavity at the ATF. 2nd International Particle Accelerator Conference (IPAC'11), Sep 2011, San Sebastian, Spain. Joint Accelerator Conferences Website, TUPO002, pp.1446-1448, 2011. <in2p3-00635065>

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